Good HD picture, poor non-HD picture

I loved the look and picture of the Sony in the showroom, but once I set it up at home, I was a little disappointed.
The HD picture in the Sony store was amazing and the HD picture in my home is pretty good. However, the non-HD picture is poor. I have the TV set-up with an HDMI cable to my DirectTV HD receiver and an HDMI cable to my Playstation 3 (Blue-ray).
HD sports and the Discovery channel look good (1080i) and the Blue-ray picture (1080p) is crisp and smooth. Colors and images on both HD sources are accurate and consistent and black levels are good.
When watching regular TV broadcasts the picture quality is very poor. I get a better picture on a cheap Korean CRT TV that I paid $99 for. Given that I only have around 10 HD channels, most of my TV viewing is non HD. I have seen other LCD makes and models in this size that retail for much less than this Sony that have comparable picture quality, I wish I would have bought one of them and saved some cash.